JP4890902B2 - Method for producing stretched thermoplastic polyester resin sheet - Google Patents

Description

The present invention relates to a method for producing a stretched thermoplastic polyester resin sheet.

Conventionally, a method for producing a transparent crystalline polymer sheet having a smooth surface and a high strength and elastic modulus by pultrusion has been studied. For example, crystals such as polyethylene, polypropylene, polyacetal resin, nylon, etc. The temperature of the base sheet of the differential polymer calorimetry melting curve is not exceeded the deformation starting temperature when the sheet is heated at a rate of temperature increase of 1 ° C./min with a 10 MPa load applied to the sheet. There has been proposed a method for producing a crystalline polymer sheet, which is drawn through at least a draw ratio of 2.5 times or more through a pair of heated rollers (see, for example, Patent Document 1).
JP 60-15120 A

Further, in the pultrusion molding, a method for producing a crystalline polymer sheet has been proposed in which the strength of the sheet after stretching is increased by quenching immediately after drawing, and the stretching speed can be increased by increasing the drawing temperature. (For example, refer to Patent Document 2).
Japanese Patent Publication No. 06-4273

However, in the above method for producing a crystalline polymer sheet, when a polyester resin is stretched, the molecular orientation is relaxed when the drawing temperature is raised, and the strength is not increased even when stretched at a high magnification, which is not desirable.
On the other hand, the flexibility required for stretching cannot be obtained at low temperatures, and voids are generated and the strength is lowered. Therefore, a stretched sheet having high strength cannot be obtained by stretching. For this reason, it is necessary to perform pultrusion molding in the temperature range of the glass transition temperature of the polyester resin −20 ° C. to the glass transition temperature + 20 ° C., and more preferably, stretching near the glass transition temperature.

  The method of providing the quenching zone not only complicates the equipment, but also when stretching the polyester resin, it is not preferable to raise the temperature of the drawing roller because orientation relaxation occurs immediately after stretching.

  Moreover, since the thickness of the stretched thermoplastic polyester resin sheet is manufactured by stretching the thermoplastic polyester resin sheet, it is as thin as 10 to 50 μm, and when used as a building material such as rain gutter, it is necessary to laminate it. There were the drawbacks that manufacturing was difficult and cost was high.

In view of the above-mentioned drawbacks, the object of the present invention is to provide a stretched thermoplastic polyester resin sheet that is excellent in tensile elastic modulus, has a small coefficient of linear expansion and shrinkage, is thick, and can be suitably used alone for building materials such as rain gutters . It is to provide a manufacturing method .

The method for producing a stretched thermoplastic polyester resin sheet according to the present invention comprises a thermoplastic polyester resin sheet in an amorphous state having a crystallinity measured by a differential scanning calorimeter of less than 10% . After preheating to a temperature higher than the glass transition temperature, the film was drawn and stretched between a pair of rolls having a temperature lower than the glass transition temperature of the thermoplastic polyester resin and a temperature equal to or higher than the “glass transition temperature−20 ° C.” of the thermoplastic polyester resin . Thereafter, the temperature is higher than the temperature of the roll and is uniaxially stretched from the rising temperature of the crystallization peak of the thermoplastic polyester resin to the rising temperature of the melting peak in the differential operation calorimetric curve measured at a heating rate of 10 ° C./min. Next, the stretched thermoplastic polyester resin sheet that was uniaxially stretched was measured at a uniaxial stretch temperature to a heating rate of 10 ° C./min. Thermoplastic polyester rising temperature of the melting peak of the resin in differential scanning calorimetry curve, heat-set in a state of uniaxial stretched oriented thermoplastic polyester resin sheet was fixed so as not to shrink by heat, tensile modulus 9 0.0 GPa or more, linear expansion coefficient of −0.2 × 10 ⁻⁵ / ° C. or less, shrinkage when held at 80 ° C. under no tension for 24 hours, 0.05% or less, width of 150 mm or more, thickness A method for producing a stretched thermoplastic polyester resin sheet having a length of 0.3 mm or more, wherein the roll is pulled in the direction of drawing at a speed substantially equal to or less than the feed speed of the stretched thermoplastic polyester resin sheet. It is characterized by rotating it.

When the tensile modulus of elasticity of the stretched thermoplastic polyester resin sheet is small, the impact resistance is lowered, so that it is 9.0 GPa or more. When the coefficient of linear expansion is large, it expands and contracts greatly due to the temperature difference. .2 × 10 ⁻⁵ / ° C. or less.

  Further, when the stretched thermoplastic polyester resin sheet is kept at 80 ° C. for 24 hours under no tension, if the shrinkage ratio is increased, the stretched thermoplastic polyester resin sheet shrinks during use. In particular, when the length of a rain gutter is shrunk, the connecting portion is broken and cannot be used.

  Moreover, in order to manufacture a rain gutter with one piece, it is necessary to be somewhat wide. Furthermore, when it is thin, the strength is weak, and it is necessary to laminate in order to have strength, but it is difficult to laminate the stretched sheet. Therefore, the stretched thermoplastic polyester resin sheet of the present invention has a width of 150 mm or more. The thickness is 0.3 mm or more. However, since it is difficult to produce an extremely thick stretched thermoplastic polyester resin sheet, it is preferably 2 mm or less, more preferably 1 mm or less.

  Examples of the thermoplastic polyester resin include polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyglycolic acid, poly (L-lactic acid), poly (3-hydroxybutyrate), and poly (3-hydroxybutyrate). / Hydroxyvalerate), poly (ε-caprolactone), polyethylene succinate, polybutylene succinate, polybutylene succinate adipate, polybutylene succinate / lactic acid, polybutylene succinate / carbonate, polybutylene succinate / terephthalate, poly Examples include butylene adipate / terephthalate, polytetramethylenadipate / terephthalate, and polybutylene succinate / adipate / terephthalate. Terephthalate is preferable.

  If the intrinsic viscosity of the thermoplastic polyester-based resin is too low, drawdown is likely to occur at the time of forming the sheet, and if it is too high, the mechanical strength (particularly the elastic modulus) does not increase even when stretched. 0 is preferred.

  Although the thickness of a thermoplastic polyester-type resin sheet is not specifically limited, 1-5 mm is preferable. If it is less than 1 mm, the sheet thickness after stretching becomes too thin, and the strength during handling may not be sufficient, and if it exceeds 5 mm, stretching may be difficult.

The thermoplastic polyester resin sheet is in an amorphous state. The degree of crystallinity of the thermoplastic polyester resin sheet is less than 10%, preferably less than 5% , as measured by a differential scanning calorimeter .

  In the above production method, a preheated amorphous polyester resin sheet in an amorphous state is drawn through a pair of rolls and drawn and stretched.

  The temperature of the thermoplastic polyester resin sheet when drawing and drawing is low, the drawn thermoplastic polyester resin sheet is whitened or too hard to tear and cannot be pulled out. Therefore, before drawing and stretching, it is preheated to a temperature higher than the glass transition temperature of the thermoplastic polyester resin, and preferably a glass transition temperature of −20 ° C. to a glass transition temperature of the thermoplastic polyester resin of + 10 ° C. It is.

  The roll temperature is lower than the preheating temperature, the film is cooled at the same time as it is stretched, and it is possible to prevent the resin temperature from rising due to frictional heat at the time of drawing and the molecular orientation is relaxed. To rise.

  When the temperature of the pair of rolls during the drawing and drawing is too low, the flexibility necessary for drawing cannot be obtained, voids are generated in the sheet during drawing, the strength is reduced, and the molecular orientation is reduced too high. Therefore, it is less than the glass transition temperature of the thermoplastic polyester resin, that is, not more than the temperature of the thermoplastic polyester resin sheet, and the “glass transition temperature of the thermoplastic polyester resin— The temperature range is “20 ° C.” or higher, preferably below the glass transition temperature of the thermoplastic polyester resin, and more than the “glass transition temperature −10 ° C.” of the thermoplastic polyester resin.

Further, when pulling out the amorphous polyester resin sheet in an amorphous state, the pair of rolls are slightly rotated in the pulling direction.

  If the rotation speed of the roll is slow, the thermoplastic polyester resin sheet is rubbed on the roll, frictional heat is generated, the roll temperature rises, and the effect of cooling the heated thermoplastic polyester resin decreases, conversely When the rotation speed of the roll is increased, only the thermoplastic polyester resin on the surface of the thermoplastic polyester resin sheet flows and cannot be drawn and drawn uniformly, and the elastic modulus of the obtained drawn and drawn thermoplastic polyester resin sheet decreases. To do.

Therefore, the rotation speed of the roll is substantially the same as or less than the feed speed of the thermoplastic polyester resin sheet , and preferably 50 to 100% of the feed speed of the thermoplastic polyester resin sheet.

  The feed rate of the thermoplastic polyester resin sheet refers to the speed before the thermoplastic polyester resin sheet enters the roll when it is pultruded without rotating the roll. The speed of the drawn stretched thermoplastic polyester resin sheet is referred to as “drawing speed”.

  In addition, when the thickness of the thermoplastic polyester resin sheet is large, the cooling effect by the roll is reduced, so that the rotation speed of the roll is preferably substantially the same as the feed speed of the thermoplastic polyester resin sheet. When the thickness of the plastic polyester resin sheet is thin, the roll rotating speed may be slow because the cooling effect by the roll is large.

  The draw ratio of the above-described drawing stretching is not particularly limited. However, if the stretching ratio is low, a sheet excellent in tensile strength and tensile elastic modulus cannot be obtained. If the stretching ratio is high, the sheet tends to break during stretching. 2-9 times is preferable, More preferably, it is 4-8 times.

The drawn thermoplastic polyester resin sheet that has been drawn and drawn is uniaxially drawn at a temperature higher than the temperature of the roll in order to improve physical properties such as tensile strength, tensile elastic modulus, and heat resistance.

  The polyester resin of the drawn stretched thermoplastic polyester resin sheet that has been drawn and drawn has high strength because the molecular chains are highly oriented with isotropic crystallization and orientation suppressed by heat, which is a hindrance to stretching. Although the elastic modulus is excellent, the degree of crystallinity is low. Therefore, when heated, the orientation is easily relaxed and the elastic modulus is lowered.

  However, the stretched thermoplastic polyester resin sheet that has been drawn and stretched is uniaxially stretched at a temperature higher than that of the roll, so that the degree of crystallinity is increased without relaxation and the orientation is easy even when heated. Thus, a stretched sheet having excellent heat resistance that is not relaxed can be obtained.

  As the uniaxial stretching method, a roll stretching method is preferably used. The roll stretching method is a method in which a stretched raw fabric is sandwiched between two pairs of rolls having different speeds, and the stretched raw fabric is pulled while being heated, and the molecular orientation can be strongly oriented only in a uniaxial direction. In this case, the speed ratio of the two pairs of rolls becomes the draw ratio.

The temperature at which the uniaxial stretching is performed is higher than the temperature of the pair of rolls at the time of drawing and stretching. However , if the temperature is too high, the drawn and stretched thermoplastic polyester resin sheet is melted and cut. It is a temperature range from the rising temperature of the crystallization peak of the thermoplastic polyester resin to the rising temperature of the melting peak in the differential operation calorie curve measured at a temperature rate of 10 ° C./min.

  The rising temperature of the crystallization peak of polyethylene terephthalate is about 120 ° C., and the rising temperature of the melting peak is about 230 ° C. Accordingly, when the polyethylene terephthalate sheet is uniaxially stretched, it is preferably uniaxially stretched at about 120 to about 230 ° C.

  The stretching ratio of the uniaxial stretching is not particularly limited. However, if the stretching ratio is low, a sheet excellent in tensile strength and tensile elastic modulus cannot be obtained. 1.1-3 times are preferable, More preferably, it is 1.2-2 times. Moreover, the total draw ratio of drawing drawing and uniaxial drawing is preferably 2.5 to 10 times for the same reason.

Furthermore, in order to improve the heat resistance of the uniaxially stretched stretched thermoplastic polyester resin sheet, it is heat-set .

If the heat setting temperature is lower than the uniaxial stretching temperature, crystallization of the thermoplastic polyester resin does not proceed, so the heat resistance does not improve, and the thermoplastic polyester system in the differential operation calorimetric curve measured at a heating rate of 10 ° C./min. When the temperature rises above the rise temperature of the melting peak of the resin, the thermoplastic polyester resin dissolves and the stretching (orientation) disappears, and the tensile modulus, tensile strength, etc. decrease, so the uniaxial stretching temperature to the heating rate of 10 ° C./min. It is the rising temperature of the melting peak of the thermoplastic polyester resin in the measured differential operation calorimetric curve.

Further, when the heat is drawn with a load on the oriented thermoplastic polyester resin sheet is applied, since the free state contracts, and of doing so fixed state so as not to shrink by heat, oriented thermoplastic Although it is not applied to the polyester resin sheet, it is preferably fixed in a state where it is not shrunk by heat, and it is preferable that no pressure is applied to the stretched thermoplastic polyester resin sheet. For example, it is preferable to heat-set in a state where both ends of the stretched thermoplastic polyester resin sheet are held with a pinch roll or the like so as not to be loaded. Therefore, heating is preferably performed with hot air, a heater, or the like.

  The time for heat setting is not particularly limited, and is generally 10 seconds to 5 minutes, although it varies depending on the thickness of the stretched thermoplastic polyester resin sheet and the heat setting temperature.

  The stretched thermoplastic polyester resin sheet of the present invention is excellent in tensile strength, tensile elastic modulus, and heat resistance, and is suitably used for building materials that require these performances.

  The stretched thermoplastic polyester resin sheet of the present invention can be used alone, but may be used by being laminated, or other unstretched thermoplastic polyester resin sheets, stretched polyolefin resin sheets, It may be laminated with a thermoplastic resin sheet such as polyolefin resin, vinyl chloride resin, ABS resin, AES resin, AS resin, or acrylate resin.

The structure of the method for producing the stretched thermoplastic polyester resin sheet of the present invention is as described above, and the stretched thermoplastic polyester resin sheet obtained has excellent tensile elastic modulus, small linear expansion coefficient and shrinkage, and thickness. Thus, it can be suitably used alone for building materials such as rain gutters.

  Next, examples of the present invention will be described, but the present invention is not limited to the following examples.

Example 1
Polyethylene terephthalate (manufactured by Unitika, product number “NEH2070”, intrinsic viscosity 0.88) was melt-extruded to obtain a polyethylene terephthalate sheet having a thickness of 3 mm and a width of 280 mm.

  The obtained polyethylene terephthalate sheet is supplied to a stretching apparatus (manufactured by Kyowa Engineering Co., Ltd.), preheated to 70 ° C., heated to 55 ° C., and rotated in the stretching direction at a speed of 0.4 m / min. The distance between the rolls (0.7 mm) was drawn at a speed of 2 m / min, drawn and drawn, then supplied to a heating bath at 200 ° C., and the outlet speed was set to 2.5 m / min and the roll was drawn. The feed rate of polyethylene terephthalate to the pair of rolls was 0.39 m / min.

  The obtained stretched polyethylene terephthalate sheet is supplied to a heating bath at 200 ° C. at a speed of 2.5 m / min, set at an outlet speed of 2.75 m / min, heat-fixed for 300 seconds, and then controlled at 120 ° C. For 5 minutes to obtain a stretched polyethylene terephthalate sheet having a stretch ratio of 5.7 times, a width of 210 mm, and a thickness of 0.63 mm.

  The polyethylene terephthalate sheet has a glass transition temperature of 76.7 ° C., a rising temperature of the crystallization peak in the differential scanning calorimetry curve measured at a heating rate of 10 ° C./min, 139.8 ° C., and a rising temperature of the melting peak. The temperature was 234 ° C.

When the tensile elastic modulus in the stretching direction of the obtained stretched polyethylene terephthalate sheet was measured according to the tensile test method of JIS K 7113, it was 9.2 GPa, and the linear expansion coefficient was −0.4 × 10 ⁻⁵ / ° C. In addition, the shrinkage rate when held at 80 ° C. for 24 hours under no tension was 0.05%.

Claims (1)

An amorphous thermoplastic polyester resin sheet having a crystallinity of less than 10% measured by a differential scanning calorimeter is preheated to a temperature equal to or higher than the glass transition temperature of the thermoplastic polyester resin, and then the thermoplastic polyester is used. After drawing and stretching between a pair of rolls having a temperature lower than the glass transition temperature of the thermoplastic resin and a temperature equal to or higher than the “glass transition temperature−20 ° C.” of the thermoplastic polyester resin, the temperature is higher than the temperature of the roll. Stretched thermoplastic polyester resin sheet uniaxially stretched from the rising temperature of the crystallization peak of the thermoplastic polyester resin to the rising temperature of the melting peak on the differential operating calorimetric curve measured at a rate of 10 ° C./min, and then uniaxially stretched The melting peak of the thermoplastic polyester resin in the differential operation calorimetric curve measured from a uniaxial stretching temperature to a heating rate of 10 ° C./min. At a rising temperature, heat-set in a state of uniaxial stretched oriented thermoplastic polyester resin sheet was fixed so as not to shrink by heat, tensile modulus than 9.0GPa, the linear expansion coefficient of -0.2 × 10 ^-5 / ° C. or less, stretched thermoplastic polyester resin having a shrinkage ratio of 0.05% or less when held at 80 ° C. for 24 hours under no tension, a width of 150 mm or more, and a thickness of 0.3 mm or more A method for producing a sheet, characterized in that the roll is rotated in the drawing direction at a speed substantially equal to or less than the feed speed of the stretched thermoplastic polyester resin sheet. Sheet manufacturing method.